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Diffstat (limited to 'src/H5Idevelop.h')
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1 files changed, 139 insertions, 0 deletions
diff --git a/src/H5Idevelop.h b/src/H5Idevelop.h new file mode 100644 index 0000000..3cd951e --- /dev/null +++ b/src/H5Idevelop.h @@ -0,0 +1,139 @@ +/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * + * Copyright by The HDF Group. * + * All rights reserved. * + * * + * This file is part of HDF5. The full HDF5 copyright notice, including * + * terms governing use, modification, and redistribution, is contained in * + * the COPYING file, which can be found at the root of the source code * + * distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases. * + * If you do not have access to either file, you may request a copy from * + * help@hdfgroup.org. * + * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ + +/* + * This file contains public declarations for the H5I (ID management) developer + * support routines. + */ + +#ifndef _H5Idevelop_H +#define _H5Idevelop_H + +/* Include package's public header */ +#include "H5Ipublic.h" /* ID management */ + +/*****************/ +/* Public Macros */ +/*****************/ + +/*******************/ +/* Public Typedefs */ +/*******************/ + +/** + * The type of the realize_cb callback for H5Iregister_future + */ +//! <!-- [H5I_future_realize_func_t_snip] --> +typedef herr_t (*H5I_future_realize_func_t)(void *future_object, hid_t *actual_object_id); +//! <!-- [H5I_future_realize_func_t_snip] --> + +/** + * The type of the discard_cb callback for H5Iregister_future + */ +//! <!-- [H5I_future_discard_func_t_snip] --> +typedef herr_t (*H5I_future_discard_func_t)(void *future_object); +//! <!-- [H5I_future_discard_func_t_snip] --> + +/********************/ +/* Public Variables */ +/********************/ + +/*********************/ +/* Public Prototypes */ +/*********************/ + +#ifdef __cplusplus +extern "C" { +#endif + +/** + * \ingroup H5I + * + * \brief Registers a "future" object under a type and returns an ID for it + * + * \param[in] type The identifier of the type of the new ID + * \param[in] object Pointer to "future" object for which a new ID is created + * \param[in] realize_cb Function pointer to realize a future object + * \param[in] discard_cb Function pointer to destroy a future object + * + * \return \hid_t{object} + * + * \details H5Iregister_future() creates and returns a new ID for a "future" object. + * Future objects are a special kind of object and represent a + * placeholder for an object that has not yet been created or opened. + * The \p realize_cb will be invoked by the HDF5 library to 'realize' + * the future object as an actual object. A call to H5Iobject_verify() + * will invoke the \p realize_cb callback and if it successfully + * returns, will return the actual object, not the future object. + * + * \details The \p type parameter is the identifier for the ID type to which + * this new future ID will belong. This identifier may have been created + * by a call to H5Iregister_type() or may be one of the HDF5 pre-defined + * ID classes (e.g. H5I_FILE, H5I_GROUP, H5I_DATASPACE, etc). + * + * \details The \p object parameter is a pointer to the memory which the new ID + * will be a reference to. This pointer will be stored by the library, + * but will not be returned to a call to H5Iobject_verify() until the + * \p realize_cb callback has returned the actual pointer for the object. + * + * A NULL value for \p object is allowed. + * + * \details The \p realize_cb parameter is a function pointer that will be + * invoked by the HDF5 library to convert a future object into an + * actual object. The \p realize_cb function may be invoked by + * H5Iobject_verify() to return the actual object for a user-defined + * ID class (i.e. an ID class registered with H5Iregister_type()) or + * internally by the HDF5 library in order to use or get information + * from an HDF5 pre-defined ID type. For example, the \p realize_cb + * for a future dataspace object will be called during the process + * of returning information from H5Sget_simple_extent_dims(). + * + * Note that although the \p realize_cb routine returns + * an ID (as a parameter) for the actual object, the HDF5 library + * will swap the actual object in that ID for the future object in + * the future ID. This ensures that the ID value for the object + * doesn't change for the user when the object is realized. + * + * Note that the \p realize_cb callback could receive a NULL value + * for a future object pointer, if one was used when H5Iregister_future() + * was initially called. This is permitted as a means of allowing + * the \p realize_cb to act as a generator of new objects, without + * requiring creation of unnecessary future objects. + * + * It is an error to pass NULL for \p realize_cb. + * + * \details The \p discard_cb parameter is a function pointer that will be + * invoked by the HDF5 library to destroy a future object. This + * callback will always be invoked for _every_ future object, whether + * the \p realize_cb is invoked on it or not. It's possible that + * the \p discard_cb is invoked on a future object without the + * \p realize_cb being invoked, e.g. when a future ID is closed without + * requiring the future object to be realized into an actual one. + * + * Note that the \p discard_cb callback could receive a NULL value + * for a future object pointer, if one was used when H5Iregister_future() + * was initially called. + * + * It is an error to pass NULL for \p discard_cb. + * + * \note The H5Iregister_future() function is primarily targeted at VOL connector + * authors and is _not_ designed for general-purpose application use. + * + */ +H5_DLL hid_t H5Iregister_future(H5I_type_t type, const void *object, H5I_future_realize_func_t realize_cb, + H5I_future_discard_func_t discard_cb); + +#ifdef __cplusplus +} +#endif + +#endif /* _H5Idevelop_H */ |